Pop-Up: Gravitational Waves: Observing Spacetime for the First Time (POP2256.02)

Hugh Crowl

Early in the morning on September 14, 2015, two 4 kilometer long laser tunnels in opposite corners of the country measured a very subtle expansion and contraction, significantly smaller than the diameter of an atom. The minuscule flexing of space, detected by the LIGO project, was caused by gravitational waves passing through Earth. These waves originated from the merger of two massive black holes in a distant galaxy, over one billion light years away. This detection of gravitational waves — the first astronomical observation ever to be carried out using something other than light — opens a brand new world of observing possibilities. In this course, we will examine the result from LIGO, study the physical principles behind gravitational waves, explore the engineering feat that allowed LIGO to make the detection, and discuss the future of gravitational wave astrophysics.